1. Field of the Invention
This invention relates to biologically active compounds and in particular to certain novel compounds exhibiting activity at thromboxane receptor sites.
2. Discussion of the Background
Thromboxane A.sub.2 (TXA.sub.2), which is derived from arachidonic acid via prostaglandin H.sub.2 (PGH.sub.2), is implicated in several potentially noxious actions on various body systems, including platelet aggregation, bronchoconstriction and pulmonary and systemic vasoconstriction. Thus TXA.sub.2 may be involved in the normal sealing of blood vessels following injury but in addition may contribute to pathological intravascular clotting or thrombosis. Moreover, the constrictor actions of TXA.sub.2 on bronchiolar, pulmonary vascular and systemic vascular smooth muscle may be important in the development of several anaphylactic conditions including bronchial asthma. There is also some evidence to implicate PGH.sub.2 and TXA.sub.2 in the genesis of inflammation.
Compounds having activity at thromboxane receptor sites, and most especially compounds which are inhibitors of thromboxane activity, are therefore of interest in one or more areas of medical treatment including the treatment of thrombotic disorders, the treatment of anaphylactic disease states, and treatments utilising anti-inflammatory agents. Compounds of this type are described and claimed in co-pending UK patent application Nos. 8000278 and 8000279 (published as GB No. 2039480A and GB No. 2039909A, respectively), U.S. Pat. Nos. 4,430,345 and 4,438,136, and in corresponding applications filed elsewhere, and also in co-pending UK patent application No. 8120364 (published as GB No. 2081258A) and in its following corresponding applications: Australian patent application No. 81/72999, Canadian patent application No. 380907, European patent application No. 81303000.4, Japanese patent application No. 81/502230, New Zealand patent application No. 197558, South African patent application No. 81/4307 and U.S. patent application Ser. No. 349,084.
The compounds described in these earlier applications contain a divalent cyclic group carrying two specific types of side chain which are required to confer the desired activity at thromboxane receptor sites. We have now found, however, that compounds containing a side chain of a markedly different type are also of interest for their activity at thromboxane receptor sites. Thus, the earlier compounds all contain a first side chain which is a 6-carboxyhex-2Z-enyl group or a modification thereof and a second side chain which may be of a wide variety of types, each of which types however contains a grouping of the form ##STR3## at the point of attachment of this second side chain to the divalent cyclic group. The compounds of the present application are quite distinct in that their second side chain does not contain such a grouping.